NGC 1365 is a giant Seyfert type galaxy in Fornax with a diameter of 200,000 light years.  It is arguably the most prominant barred spiral in the sky.  The bar rotates clockwise with velocities in the nucleus of 2000 km/sec resulting in one rotation in 350 million years.  The knots seen along the bar are areas of intense star formation which occurs because the bar funnels material into this area to trigger star formation.  It is thought that the nucleus contains a super massive black hole among the dust lanes visible in the image.The gravitational pertubation from the rotating bar form the very elongated spiral arms that are often difficult to capture in their entirety in optical images.  These too have large knots of star forming areas.The seeing recorded on the Gemini South monitor on Cerro Pachon, 5 km away from PROMPT2, was recorded as low as 0.53 arc sec during the acquistion of the luminance data.

Image Date: 01/11/2007
Details: Exposure Time: 3 hrs Lum; 3 hrs RGB
Camera: Apogee  U47
Telescope: RC Optical  16" f/11.3 truss
Mount: Software Bisque  Paramount ME


  1. Hal Heaton

    Was the exposure time on this image also 10-min in each of the color channels and 15-min for the Luminance image as you indicated it was for the other image of this galaxy (14.5″ scope at f/8.2) on your website in response to my query last week. I’m asking because I’m doing image planning on Chilescope.

    • astrodon

      All I could find for this old image is that the luminance exposure was 10 minutes. Don’t forget this was taken on a larger (16″) but much slower (f11.3) scope with a high-QE backthinned CCD camera (U47). So, making direct comparisons with the other scope may not be so easy.

      • Hal Heaton

        Thanks for that helpful info and advice. Your image is really spectacular!


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